Wireless communications systems are used in a variety of telecommunications systems, television, radio and other media systems, data communication networks, and other systems to convey information between remote points using wireless transmitters and wireless receivers. A transmitter is an electronic device which, usually with the aid of an antenna, propagates an electromagnetic signal such as radio, television, or other telecommunications. Transmitters often include digital signal processing circuits which encode a data signal, upconverts it to a radio frequency signal, and passes it signal amplifiers which receive the radio-frequency, amplify the signal by a predetermined gain, and transmit the amplified signal through an antenna. On the other hand, a receiver is an electronic device which, also usually with the aid of an antenna, receives and processes a wireless electromagnetic signal. In certain instances, a transmitter and receiver may be combined into a single device called a transceiver.
Many wireless transceivers, particularly in those integral to handheld wireless devices (e.g., cellular phones) may suffer from over-the-air performance degradation due to what has been termed in the industry as “hand and head effects.” Hand and head effects may occur as a result of proximity of a user's head, hand, or other body part to an antenna of the transceiver. The proximity of such body parts to an antenna may cause a change in electrical properties of the antenna, for example changes in the effective load resistance, load capacitance, or load inductance. These changes in electrical characteristics can cause variations in the ratio of incident power to reflected power transmitted to an antenna, which may lead to performance degradation in transmitted signals.